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SEGMENT INFORMATION - Reconciliation of Operating Segment Income (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023
Segment Reporting Information [Line Items] |  |  |
Unallocated expenses | $ (53,309) | $ (46,610) | $ (65,956)
Depreciation and amortization | (124,533) | (121,018) | (115,524)
Interest expense, net | (33,269) | (35,584) | (35,232)
Loss on extinguishment of debt | (795) | 0 | 0
Asset impairment charges | (214,386) | 0 | 0
Stock-based compensation | (23,561) | (20,300) | (21,101)
Transaction costs | (291) | (140) | (968)
Gain on purchase of business | (6,243) | 0 | 0
Loss on assets held for sale | (257) | (733) | (7,477)
Other | (1,649) | (6,701) | (11,535)
(Loss) Income before income taxes | (18,590) | 587,237 | 850,290
Operating Segments |  |  |
Segment Reporting Information [Line Items] |  |  |
Adjusted EBITDA | 439,703 | 818,323 | 1,108,083
Operating Segments | Electrical |  |  |
Segment Reporting Information [Line Items] |  |  |
Adjusted EBITDA | 330,512 | 728,341 | 1,004,853
Operating Segments | Safety & Infrastructure |  |  |
Segment Reporting Information [Line Items] |  |  |
Adjusted EBITDA | $ 109,191 | $ 89,982 | $ 103,231

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